I think I read about this on this forum, but I really can't remember what I read.
I have read that the reason that 110 grain .357 magnum rounds were hard on the forcing cone of a K frame because of the jump from the cylinder to the barrel allowed gases to escape and cause flame cutting to the top strap and erosion of the forcing cone. I think that's what I read. That the 158 grain .357's were closer to the cone and kept the gases from escaping better than the 110 grain screamers.
Now, here's my question: Isn't a .38 special +P round even shorter than a 110 grain.357, and wouldn't that allow even more gas to escape. I have never shot a .38 special in my .357 magnum model 65, only 158 grainers. I wound up with 2 boxes of 125 grain .38 special +P's and thought about shooting some of them to see how they hit.
If you believe that they are totally safe to shoot in my 65 then I would like to know how that could be, given the difference in the length of the shell.
Just wondering. I'm sure somebody on here know the answer. The 38 +P's I have are the Winchester white box kind.
Thank you for your input!
Peace,
gordon

I had 100 rounds of 125-gr. .38 +P that I thought I'd run through my 4-inch Python. The muzzle blast and flash was so intense that I fired two cylinders and reverted to either .38 wadcutters or reasonably loaded 158-gr. .357s. My impression was that over time a steady diet of these hot .38s would accelerate wear on the gun. I wouldn't think that 100 rounds would tear up your gun, but I'm no expert.

I've read about this too, and still don't totally understand it. I know this is also true for the new Scandium framed guns. You mentioned the K-Frame revolvers, I would like to know if the .357 Magnum 110 grn loads will have this effect on other size guns. I used to carry them in my 640-1 and never saw a problem, and I've probably shot them in my 27-2. Will they cause problems in these?

I've always thought it was B.S., like the old tale that I shouldn't fire my early 03 Springfield. It's worn out at least 3 barrels, but the frame isn't properly heat treated, so it's dangerous. I've never seen a K frame revolver in person with a cracked forcing cone. My 19 is marked "357 Magnum". That's what I'm going to shoot in it.

I would like to know how that could be, given the difference in the length of the shell.

Itís not the length of the shell itís the overall length of the round. Remember that the 38 special round is 1/8Ē shorter than the .357 Magnum round, so any excess gases will be forced forward in the charging hole, when the hot gases reach the gap between the end of the cylinder and the forcing cone it will be traveling in a straight line and will generally continue in that direction, so any gas escaping upward or to the sides will be lessened. Lastly remember the max pressure of the 38 special round is 18,000 PSI and the max pressure of the .357 Magnum round is right around 35,000 PSI.

What will happen when shooting 38 special ammo in a revolver chambered for .357 Magnum is a carbon ring will develop in the charging holes.

As for the forcing cone damage remember that the M-19 has a smaller forcing cone than the M-27, and the M-19 forcing cone has a flat spot on the bottom, whereas the M-27 does not have a flat spot on the forcing cone.

110 gr. .357 Mags were not the problem. It was the 125 gr. rounds. 125s were always loaded much hotter than the 110s so shoot all the 110s you want. The newer Remington 125 grain Golden Saber are loaded to lesser velocity than the old 125s from the 70's for this specific reason.. You can shoot all the +P and +P+ .38s you want in a .357. The only problem you'll have with them is a build up of carbon in the cylinder that will make it hard to get the .357s to chamber properly.

110 gr. .357 Mags were not the problem. It was the 125 gr. rounds. 125s were always loaded much hotter than the 110s so shoot all the 110s you want. The newer Remington 125 grain Golden Saber are loaded to lesser velocity than the old 125s from the 70's for this specific reason.. You can shoot all the +P and +P+ .38s you want in a .357. The only problem you'll have with them is a build up of carbon in the cylinder that will make it hard to get the .357s to chamber properly.

AZretired is right. The hottest loads are the 125s from Federal and Remington. The 125 grain Golden Sabers are easy on you and the gun, but very effective.

As others have noted, the current Winchester .38 125 gr +P is rated at 925 fps out of a test barrel, with the same weight full load .357 at about 1300 fps. I've shot the former out of 2" snubbies and found it to be a nice plinking load.

I am a real amateur and still learning about wheel guns and shooting and ammo, so please excuse a noob, and thanks for your patience.

I am interested in this discussion as I own a 13-1, which if I read other posts is nearly identical to the 19. I also read the other discussions about the potential for my 13-1 forcing cone cracking. After reading those posts I stopped carrying and shooting my 13-1. I understand to a very limited degree the explanation, but I still have questions.

I have a bunch of 125 gr, some 158 gr, and some 110 gr, all either SP or HP, and they look to be all the same overall length, within a whisker. Even the same bullet from different manufacturers are the same length. The only difference then is the bullet weight and fps.

I took some factory data from an internet retail site just to use as an example, and I understand fps is not psi. The Remington rounds (I have several boxes of each, alone with a bunch of the Winchester) look very close in velocity - 1220 fps to 1450 fps. Is the 1450 too high for my 13-1? The 1600 fps for the DoubleTap is higher, is it THAT so much higher that it shouldn't be used in my 13-1? I have a box of these, too. Most retailers don't list the psi ratings of each bullet but the fps is easy to find. Are any of these listed below the "hot loads" and should not be used in my 13-1?

I thought it had less to do with gas, copper jackets, or anything else than the energy of the bullet with it hits the forcing cone. the hot 1,400 fps and up 125's hit those forcing cones with a whole lot more energy that the 158's that the gun was designed around. All the horror stories I have read on this subject didn't seem to start big time until the 125 screamer's started going into use. It seems counter intuitive at first that a heavy bullet would hit softer than a lighter bullet but it's all about how much energy bleeds off into the forcing cone. I'm sure if you were to load up a 158 up to the same velocity as the 125 screamer's then you would get the same troubles. But I still look at a different way. If S&W has decided they don't want to make any more K frame magnum barrels then why would I be in a hurry to wear mine out? So the max 125 I would use is a Golden Saber or similar FPS load or a nice mild to medium 158 or I just shoot all the .38 special that I want.

110 gr. .357 Mags were not the problem. It was the 125 gr. rounds. 125s were always loaded much hotter than the 110s so shoot all the 110s you want. The newer Remington 125 grain Golden Saber are loaded to lesser velocity than the old 125s from the 70's for this specific reason.. You can shoot all the +P and +P+ .38s you want in a .357. The only problem you'll have with them is a build up of carbon in the cylinder that will make it hard to get the .357s to chamber properly.

AAAAARGH!!!! What he said.^^^^^^^^ The confusion, misinformation and disinformation about this is about to wear out this old-timer. The bullet weight is mostly irrelevant. The 125 grain factory loads are loaded MUCH hotter than 110s, and if one works at it, he can damage a gun with ANY bullet weight. The only way that the weight or length of the bullet matters is that by the time you get enough powder behind a 158gr. or heavier bullet to cause progressive forcing cone damage, you're at a level of potential catastrophic failure.

I thought it had less to do with gas, copper jackets, or anything else than the energy of the bullet with it hits the forcing cone. the hot 1,400 fps and up 125's hit those forcing cones with a whole lot more energy that the 158's that the gun was designed around. All the horror stories I have read on this subject didn't seem to start big time until the 125 screamer's started going into use. It seems counter intuitive at first that a heavy bullet would hit softer than a lighter bullet but it's all about how much energy bleeds off into the forcing cone . . .

^^^ This.

The energy that Maximumbob refers to can be calculated using the equation for kinetic energy, E=1/2MV^2. There's a gravitational constant in there, too,

That's one half the mass times the square of the velocity. Change the velocity and energy changes as a square function. Change the bullet mass (weight for non-science types) and the energy changes linearly. Thus, mass changes have little effect on energy whereas velocity changes have a huge effect.

For example:

V1 = 1200 FPS V^2 = 1,440,000 504 ft-lbf

V2 = 1400 FPS V^2 = 1,960,000

V3 = 1600 FPS V^2 = 2,560,000

That's the power of varying a square function. Increase the velocity only 400 FPS and the square of the velocity increases 78%.

Using the velocities in the above example:

158 gr bullet @ 1200 FPS E = 504 ft-lbf (lbf = pounds force)

125 gr bullet @ 1600 FPS E = 710 ft-lbf

The lighter bullet has way more energy when going faster. 41% more. That's the problem with fast 125s in a K frame. 41% more energy hitting a forcing cone that's thin to begin with.

Think of it like this: Hit something with a three-pound hammer at one velocity and then hit the same object with a four-pound hammer going 25% slower, and the energy is MUCH less with the heavier but slower hammer.

What's the energy of a 125 gr bullet at 1200 FPS, for an apples-apples comparison?

125 gr bullet @ 1200 FPS E = 399 ft-lbf That's only 80% of the energy of the 158 gr bullet at the same velocity.

And a 158 gr bullet @ 1600 FPS?

158 gr bullet @ 1600 FPS E = 897 ft-lbf

Sometimes non-science types have problems wrapping their heads around the concept of the power of a square function in a mathematical equation. I tried to explain this at the PA Firearms Owners forum and was called full of excrement because everybody knows a heavier bullet has more energy. Fact is, you can't make that statement without specifying the velocity. Just like you can't define the density of water without specifying the temperature at which the density of water is being measured. (The colder water gets, the density drops. Molecules of H2O get farther apart. That's why ice floats; it has a lower density than liquid water, whose is 1 gm/cubic centimeter at 20C / 68F).

The problem came when heavy shooters and police departments went from the thought process of "carry 357's, practice with 38's", to practice exclusively with what you carry after the Newhall incident. The gun was made for 158 grain rounds using 1950's powders. Bill Jordan also expected the gun to have many more 38's shot through than 357's.

Shooting guns obviously causes the metal to warm up. The flat spot on the K-frame forcing cone (at the 6 o'clock position) could get so hot that it would crack from the heat and pressures delivered by the hotter 125 grain rounds.

I've personally seen several model 19's with cracks in the forcing cone at gun stores. Needless to say, the guys behind the counter were NOT happy when I told them what they had.

A model 19 or 66 will be fine shooting 125 grain 357 rounds in moderation.

EDIT TO ADD: take a close look at the current 357's made by S&W and you'll see a piece of steel on the bottom side of the top strap above the barrel/cylinder gap to keep the heat and gasses from damaging the metal.

Interesting thread, thought i'd comment on this old thread to correct the water analogy.. cold water is denser than warm water, that's why when you see lake maps of the water the cold water is at the bottom and warm at the top, or cold air falling towards earth and warm air rising... the exception is when water turns solid into ice it expands and becomes less dense as a solid, and hense floats.